Head for chimneys and air-shafts



April 12, 1938. ,A. BUHRER 2,114,164

HEAD FOR CHIMNEYS AND AIR SHAFTS Filed Oct. so, 1956 7 j W ii [nae nl'or Patented Apr. 12, 1938 STATES PATENT OFFICE Application October 30, 1936, Serial No. 108,445 In Switzerland November 1, 1935 3 Claims.

My invention relates to improvements in smoke deflector or sucker heads straddling and coveringthe openings of chimneys and air-shafts; and the objects of my improvement are, first, to provide for a sucking action of the wind on the chimney opening; and second, to keep said action unimpaired in falling winds or downwinds.

I attain these objects by the device illustrated in in the accompanying drawing, in which- Fig. 1 is a vertical section of the entire device and the chimney top;

Fig. 2, a top plan view of the device; and

Fig. 3, a second example of design in vertical section.

A circumferential bulge b, comprising two parts of conical surfaces and d, is rigidly fastened to the top of the chimney a. Straps e, attached to the top part of said bulge at suitable intervals, carry at their outer ends the peened bottom of a sheet-iron cylinder f in rigid connection. Said cylinder is open on top and bottom and is held co-axially with the chimney-top, and its bottom edge g is lying at the height of the top rim of the said surface at. The diameter of said cylinder is such that an annular channel h is set free between it and said bulge-ring cd. Straps i are fastened, at suitable intervals, to the top rim of said cylinder at one end and at their other end to the top of a second sheet-iron cylinder 7c. The latter possesses a conical top and bottom cover and is suspended co-axially with the first cylinder, and its diameter is materially greater than that of the chimney-top. The apex of the conical bottom of the said cylinder 70 is set at some distance above the chimney-top. Rain running down the vertical side m of the cylinder is will drop oil the circumferential lip-bulge l 1 formed by joining the bottom n and the side m onto the top part c of the said annular bulge c-d and thence onto the roof. Between the said cylinders f and k a second annular channel 0 is set free through which the smoke or the i3 flue-gases may escape into the atmosphere.

In order to increase the sucking action of horizontal air currents on the chimney draft, two identical hollow annular frusta of cones qi and (12, the bottom circles of which coincide,

50 may be mounted on the outside circumference of the outer cylinder f, the total height of which equals that of the latter.

The action of the present head of chimney is the following: With the wind blowing horizontally, a zone of increased pressure is built up and maintained in both the lower and upper annular channels h and 0 which, from within the chimney, is constantly fed. An accelerated speed of evacuation is thus attained for the smoke rising out of the chimney or, similarly, for the spent air drawn out of an air-shaft, When, however, the wind is blowing in an upward sense, or-which is even more unfavorable for the purposes of heating or ventilationwhen it is dropping more or less in a vertical sense onto the chimney, the atmospheric air flowing parallel to the axis of the chimney through the annular channels h and 0 produces a vacuum in the conically enlarged diffusor space p. The latter is formed by the conical surfaces 0 and n of, respectively, the bulge-ring c-d and of the hollow cylinder 70. The wind therefore may blow in any direction without ever causing a flow back into the chimney which would jeopardize the chimney draft or the correct functioning of the ventilation through the airshaft.

My present invention yet fulfills another purpose. It is well known that the chimney draft particularly in the summer and in a bright sun is very much decreased, since the necessary difference and drop of temperature then is lacking on account of the relatively high outside temperature. In order then to eliminate or, at least, materially to reduce the damaging influence of said phenomenon, the air-filled hollow cylinder it serves as heat-insulating unit so that the air underneath the latter is heated but to a small extent. Due to a similar insulating effect of the bulge-ring b enclosing the top of the chimney, said insulating effect is extended to some distance below the top of the chimney so that the operation of the heating plant does not meet any difiiculties, so much less since, moreover, at most times the simultaneous sucking action of a wind current is existing.

What I claim and desire to secure by Letters Patent is:

1. In a head for chimney and air shaft openings the combination of: a sleeve having a cylindrical body portion and conical upper and lower side faces surrounding the said chimney adjacent the upper end thereof; an outer cylinder connected at the lower end thereof to said sleeve; a central member suspended within said outer cylinder and connected at the upper end thereof adjacent to the upper end of said outer cylinder; said central member having a cylindrical body portion and a conical bottom face and the axes of said central member and said outer cylinder being coaxial with that of said chimney shaft and the diameters of said sleeve and said central member being less than that of said outer cylinder, so that an annular channel is formed between said sleeve and said outer cylinder and between the latter and said central member, at least over a part of the circumference, and the upper conical face and the cylindrical body portion of said sleeve and the body portion and bottom face of said central member lying wholly within said outer cylinder.

2. In a head for chimney and air shaft openings the combination of: a sleeve having a cylindrical body portion and conical upper and lower side faces surrounding the said chimney adjacent the upper end thereof; an outer cylinder connected at the lower end thereof to said sleeve; a central member suspended within said outer cylinder and connected at the upper end thereof adjacent the upper end of said outer cylinder; said central member having a cylindrical body portion anda conical bottom face and the axes of said central member and said outer cylinder being coaxial with that of said chimney shaft and the diameters of said sleeve and said central member being less than that of said outer cylinder, so that an annular channel is formed between said sleeve and said outer cylinder and between the latter and said central member, at least over a part of the circumference, the upper conical face and the cylindrical body portion of said sleeve and the body portion and bottom face of said central member lying wholly within said outer cylinder; and the said upper conical face of said sleeve and said bot tom face of said central member having a common apex on the vertical main axis of said head.

3. In a head for chimney and air shaft openings the combination of: a sleeve having a cylindrical body portion and conical upper and lower side faces surrounding the said chimney adjacent the upper end thereof; an outer cylinder connected at the lower end thereof to said sleeve; two annular conical frusta having coinciding base circumferences on the outer surface of said outer cylinder and being of a height equal to that of said cylinder; a central member suspended within said outer cylinder and connected at the upper end thereof adjacent to the upper end of said outer cylinder; said central member having a cylindrical body portion and a conical bottom face and the axes of said central member and said outer cylinder being coaxial with that of said chimney shaft and the diameters of said sleeve and said central member being less than that of said outer cylinder, so that an annular channel is formed between said sleeve and said outer cylinder and between the latter and said central member, at least over a part of the circumference, and the upper conical face and the cylindrical body portion of said sleeve and the body portion and bottom face of said central member lying wholly within said outer cylinder.

ADOLF BI'JHRER. 

